1. Field of the Invention
The present invention relates to a water-proofing structure, and more particularly relates to a water-proofing structure for a case containing electrical contacts or control circuits.
2. Description of Related Art
Electrical contacts for position detection or control circuits for a motor are integrally contained within a gear case in motors used for a vehicular power window or vehicular door-locking apparatus, for an overall compactness. In this type of motors, since there is a possibility of the motors getting wet, a perfect water-proof of the gear case is required. In addition, since temperature rises within the case when the motor is in operation and lowers when the motor is not in operation, negative pressure might be generated therein due to this temperature changes. Therefore, it is also necessary to ensure water-proofing in order to prevent water inflow from the outside to the inside of the case.
JP-U-6-29363 discloses, for example, a structure wherein sealant receiving grooves are provided on the abutting surfaces of the case body and the case cover respectively, and viscous resin sealant is filled therein for water-proofing.
However, in this conventional water-proofing structure, the sealant overflows largely from the abutting portion where the case body and the case cover meet. Here, butyl rubber can be normally used as sealant for example. However, when the rubber enters in large amount into the case, the rubber might adhere to the electrical contacts provided in the case resulting in blocking the electrical conduction, for the butyl rubber is a good insulating material.
Also, in order to improve the sealing property, it is required to secure a large enough contacting area in the abutting surfaces for the sealant sandwiched. However, since the conventional water-proofing structure can not have the other way than enlarging the abutting surface area where the case body and the case cover meet, the case has to be designed larger in an overall size.